92 240SX m/t - key off drain from ECU after car has run and been shut down

[Hype]

Thus far, I've avoided this problem for the most part by simply unplugging the negative cable to the battery, but I'm fed up now. I managed to find out that it draws .5 amp after the car has been turned off after running. If I take power away from the ECU by removing the negative cable and putting it back, then it only draws the 20 or so mA that it should for the clock, stereo memory etc.

http://www.incdamage.net/ecu_fuse.png In the fuse box near the battery, I pulled the 25A fuse labeled "Eng Cont" and it fixed my drain. I guess what I need to do now is possibly look for a bad ECU ground. Has anyone run into something similar, or have any suggestions?

zerothread?id=219753 Cpt_Impossible had very nearly the same problem, but his because of a bad RB swap wiring job

Thanks in advance for any input.